512
FXUS65 KBYZ 210126
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
626 PM MST MON JAN 20 2025
KEY MESSAGES
- VERY COLD TEMPERATURES THROUGH TUESDAY MORNING. DRESS FOR THE
TEMPERATURES BEFORE HEADING OUTSIDE.
- HIGH WINDS EXPECTED IN THE FOOTHILLS WEST OF BILLINGS TONIGHT
THROUGH TUESDAY EVENING. PATCHY BLOWING SNOW MAY OCCUR WITH
THESE WINDS.
- WARMER TEMPERATURES RETURN TUESDAY.
- LIGHT SNOW AND BLOWING SNOW POTENTIAL ACROSS SOUTHEAST MONTANA
TUESDAY NIGHT AND WEDNESDAY.
- ANOTHER PERIOD OF ACCUMULATING SNOW IS POSSIBLE FRIDAY INTO
SATURDAY.
UPDATE
NORTHERLY FLOW ALOFT HAS BECOME ANTICYCLONIC, AND WE ARE STARTING
TO ADVECT SOME HIGH CLOUDS SPILLING OVER A HIGH AMPLITUDE RIDGE
TO OUR WEST THAT IS EXTENDING INTO BC/AB. THE KLONDIKE CHINOOK IS
UNDERWAY. LATEST IDA-LWT PRESSURE GRADIENT IS TIGHTENING QUICKLY
AND IS UP TO 14.7MB AS OF 01Z. BIG TIMBER AND HARLOWTON ARE
GUSTING 40-50 MPH, BUT LIVINGSTON IS MUCH LOWER DUE TO THE
ORIENTATION OF THE GRADIENT, WHICH FAVORS THE NON-GAP LOCATIONS
ALONG OUR WESTERN FOOTHILLS UNDER NORTHERLY FLOW. WILSALL IS 1F
AND THE AIRPORT IS DRAINING THE SHIELDS VALLEY. OVER THE HILL IT
IS -2F AT BOZEMAN. DESPITE THE RAPIDLY FALLING PRESSURES THERE ARE
SEVERAL REASONS FOR LIVINGSTON TO NOT REALIZE ITS GAP POTENTIAL
UNTIL EARLY TUESDAY WHEN THE MID LEVEL WINDS BACK MORE WESTERLY.
OVERALL, THE WIND HIGHLIGHTS LOOK ON TRACK, BUT DID ADJUST
TONIGHT'S WINDS SOME...GOING HIGHER GUSTS EARLIER AT BIG TIMBER &
HARLOWTON, AND HOLDING OFF LIVINGSTON UNTIL LATE TONIGHT. ALSO,
SOME VALLEY LOCATIONS IN OUR EAST HAVE ALREADY EXCEEDED FORECAST
LOWS AND HAVE MADE ADJUSTMENTS. IT IS -8F AT HARDIN AND -7 AT
SHERIDAN, FOR EXAMPLE. OF COURSE, WE WILL SEE MODERATING TEMPS
THRU THE NIGHT W/ THE DOWNSLOPE WARMING...SO NIGHTTIME "LOW" TEMPS
ARE FAIRLY MEANINGLESS. JKL
DISCUSSION
TONIGHT THROUGH WEDNESDAY NIGHT...
WARM AIR ADVECTION WILL CONTINUE TONIGHT BRINGING SEASONAL
TEMPERATURES IN THE MID 20S TO MID 30S TOMORROW. THE WARMER
TEMPERATURES WILL CREATE LOW PRESSURE OVER THE PLAINS SETTING UP A
STRONG PRESSURE GRADIENT FOR THE WESTERN FOOTHILLS. GUIDANCE
INDICATES THE IDAHO FALLS TO LEWISTOWN PRESSURE GRADIENT WILL GET
INTO THE 20S MB. 700MB WINDS WILL BE IN THE 45-55KT RANGE,
INCREASING CONFIDENCE IN STRONG WINDS. TONIGHT, THE FOOTHILLS WILL
HAVE A STRONG INVERSION BRINGING THE BEST SETUP FOR GAP AREAS.
TOMORROW THE INVERSION WILL STRUGGLE TO BREAK. HOWEVER, THE 700MB
WINDS AND PRESSURE GRADIENT WILL BE ENOUGH TO BRING STRONG WINDS
TO NON-GAP AREAS. MOST OF THE FOOTHILLS WILL HAVE A >75% CHANCE
OF GETTING A GUST OVER 50MPH AND LIVINGSTON HAVING A 50% CHANCE OF
GETTING A GUST OVER 75MPH. AS WE MOVE INTO WEDNESDAY, THE UPPER
LEVEL TROUGH WILL BRING PRESSURE RISES TO THE PLAINS WEAKENING THE
FOOTHILLS PRESSURE GRADIENT. THIS WILL WEAKEN FOOTHILLS WINDS,
THOUGH THE WINDS WILL REMAIN BREEZY.
WEDNESDAY, AN UPPER LEVEL TROUGH WILL BRING EMBEDDED SHORTWAVES
AND SNOW CHANCES TO THE REGION. SNOW AMOUNTS LOOK TO REMAIN LIGHT
WITH THE CHANCE FOR GREATER THAN 2 INCHES BEING LESS THAN 50%
ACROSS THE REGION. HOWEVER, WINDS WILL BE GUSTING INTO THE 30S
AND 40S MPH LEADING TO BLOWING SNOW AND VISIBILITY CONCERNS,
ESPECIALLY FOR LOCATIONS EAST OF BILLINGS. THERE IS LITTLE TO NO
SNOWPACK ACROSS THE REGION SO ANY BLOWING SNOW WILL HAVE TO COME
FROM NEW SNOWFALL. TORGERSON
THURSDAY THROUGH MONDAY...
THURSDAY WILL BE A PRE-FRONTAL DAY WITH A PACIFIC FRONT ARRIVING
FROM THE NORTHWEST THURSDAY EVENING. THERE IS THE POTENTIAL FOR
ANOTHER ROUND OF STRONG FOOTHILLS WINDS FROM LIVINGSTON AND NYE,
NORTH THROUGH BIG TIMBER AND HARLOWTON. ELSEWHERE BREEZY TO
LOCALLY WINDY CONDITIONS ARE ANTICIPATED. DOWNSLOPE WINDS AND
EARLY DAY SUNSHINE WILL PUSH TEMPERATURES ABOVE FREEZING FROM
BILLINGS WEST, WHILE EASTERN AREAS STAY IN THE 20S FOR HIGHS.
PRECIPITATON CHANCES INCREASE THURSDAY EVENING, BECOMING LIKELY
IN MANY AREAS BEFORE SUNRISE FRIDAY. DURING THE DAY FRIDAY WILL
SEE PRECIPITATION BECOME MORE FOCUSED SOUTH AND WEST OF A
HARLOWTON TO BILLINGS TO SHERIDAN LINE. LATEST GUIDANCE SHOWING
ADVISORY LEVEL SNOWFALL ALONG AND SOUTH OF I-90 FROM EARLY FRIDAY
THROUGH SATURDAY MORNING, WITH HEAVIER POTENTIAL OVER THE HIGHER
MOUNTAINS. UNCERTAINTY WITH SNOWFALL AMOUNTS WITH THIS SYSTEM
HINGE ON A PIECE OF ENERGY RIDING THE WESTERN EDGE OF THE UPPER
TROF THAT HELPS TO PULL COLDER AIR AND ENERGY FURTHER WEST AND
TURN WINDS MORE UPSLOPE THAN THE INITIAL TROF WOULD INDICATE ON
ITS OWN. WILL SEE IF THIS TROF RIDING FEATURE CONTINUES AS WE GO
THROUGH THIS WEEK.
BEHIND THE FRIDAY SYSTEM THE AREA STAYS UNDER NORTHERLY FLOW ALOFT
WHICH WILL KEEP TEMPERATURES BELOW NORMAL (SAT/SUN) TO NEAR NORMAL
BY MONDAY. THERE ARE A FEW WEAK DISTURBANCES IN THIS FLOW THAT
COULD BRING ADDITIONAL LIGHT SNOW/FLURRIES THROUGH THE WEEKEND.
CHAMBERS
AVIATION
VFR CONDITIONS WILL PREVAIL THROUGH TONIGHT, WITH VFR CEILINGS
DROPPING TO AROUND 10KFT AGL BY SUNRISE TUESDAY. WINDS WILL BE
INCREASING OVER THE WESTERN FOOTHILLS THIS EVENING, BECOMING
STRONG OVERNIGHT. GUSTS AROUND 60KTS ARE EXPECTED FOR KLVM BY 12Z
AND 50KTS IN K6S0. GUSTY WINDS WILL SPREAD EASTWARD ACROSS THE
LOWER ELEVATIONS OVERNIGHT INTO TUESDAY MORNING. STRONGER GUSTS
OF 30 TO 40KTS ARE POSSIBLE OVER HIGHER EXPOSED TERRAIN, WHILE
MORE SHELTERED LOCATIONS WILL SEE INCREASED WIND SHEAR POTENTIAL.
BLOWING SNOW DOES NOT APPEAR TO BE A BIG CONCERN OVER WESTERN
FOOTHILLS AREAS DUE TO A LACK OF RECENT SNOWFALL. HOWEVER AREAS
FROM NEAR BILLINGS EAST TO THE STATE LINE HAVE A BETTER POTENTIAL
FOR BLOWING AND DRIFTING SNOW IMPACTS AS WINDS INCREASE OVERNIGHT
INTO TOMORROW. FOR NOW HAVE A MENTION OF BLOWING SNOW IN KBIL/KMLS
TAFS WITH MINOR VISIBILITY REDUCTION, BUT THIS MAY NEED TO BE
ADJUSTED AS WE SEE WHAT HAPPENS AS WINDS INCREASE. A FEW LIGHT
SNOW SHOWERS DEVELOP OVER CENTRAL AREAS INCLUDING KBIL TUESDAY
MORNING BUT SHOULD NOT IMPACT FLIGHT CATEGORIES. CHAMBERS
PRELIMINARY POINT TEMP/POPS
TUE WED THU FRI SAT SUN MON
-----------------------------------------------------------
BIL 003/033 021/032 013/033 024/031 013/023 005/023 012/032
01/Q 23/J 10/B 57/S 42/S 11/B 00/U
LVM 010/032 017/029 012/035 023/029 009/019 001/024 012/036
00/N 21/N 01/N 57/S 41/B 10/B 00/U
HDN 910/034 021/032 009/034 021/032 013/023 901/023 006/033
01/E 57/J 20/U 57/S 42/S 11/B 11/U
MLS 910/030 021/027 009/028 020/028 012/019 001/021 007/028
01/Q 36/J 30/B 43/S 11/E 00/B 11/B
4BQ 910/032 022/026 013/029 021/029 014/019 003/023 008/031
00/E 58/J 50/U 33/S 21/E 11/B 11/U
BHK 919/027 016/024 009/025 013/026 008/017 901/019 005/028
02/J 45/J 40/B 42/S 10/E 00/B 00/B
SHR 911/037 016/027 010/033 016/029 009/020 904/025 005/036
00/B 58/J 20/U 37/S 53/S 11/B 11/U
BYZ WATCHES/WARNINGS/ADVISORIES
MT...COLD WEATHER ADVISORY IN EFFECT UNTIL 11 AM MST TUESDAY FOR
ZONES 32-33-36-37.
HIGH WIND WARNING IN EFFECT FROM 2 AM TO 11 PM MST TUESDAY
FOR ZONES 63-172-228.
HIGH WIND WARNING IN EFFECT UNTIL 11 PM MST TUESDAY FOR ZONES
65-66-141.
WY...NONE.
WEATHER.GOV/BILLINGS
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